RLO Transcript: Heart Failure
This is a transcript of the Reusable Learning Object (RLO) entitled "Heart Failure", online at:

http://www.nottingham.ac.uk/nursing/sonet/rlos/bioproc/heart_failure/

Introduction
The heart is a hollow muscular organ that pumps blood around the body. It has four chambers – the upper chambers are the atria and the lower chambers are the ventricles. The heart is really two pumps connected in series – the left and right sides. The right side pumps deoxygenated blood to the lungs and the left pumps oxygenated blood around the body.
Cardiac Output
When at rest, the typical heart rate is about 70 beats per minute and at each contraction the left ventricle ejects about 70 ml – a measurement termed the stroke volume. We can calculate the cardiac output (that is the volume that the heart pumps each minute) by multiplying the two figures. The result is approximately 5 litres per minute. When we engage in activity the exercising muscles require an increased amount of oxygen and the response of the body is to increase cardiac output by raising both pulse rate and stroke volume.   
Heart Failure
Heart failure is the condition that exists when the heart cannot maintain a sufficient cardiac output to meet the metabolic demands of the body. In the failing heart the stroke volume is reduced, and as a consequence the cardiac output also falls.
Acute and Chronic Heart Failure
Acute heart failure occurs when there is a sudden and severe impairment of cardiac function such as occurs in myocardial infarction (that is, a heart attack). Chronic heart failure occurs mainly as a consequence of ischaemic heart disease and the effects develop over months and years. In this case the patient’s body compensates for the slowly developing condition. For example the heart enlarges just as any stressed muscle is able to do.
Left Ventricular Failure
Heart failure affecting the left side (that is left ventricular failure) leads to a fall in stroke volume and cardiac output that tends towards a reduction in arterial blood pressure and the development of pallor. The body attempts to compensate for this by raising the heart rate. The pulse it is fast, but because of low stroke volume it also feels weak or "thready"

In addition, the left side of the heart is unable to “clear” blood flowing to it from the lungs and a “backlog” develops. This causes pulmonary hypertension (elevated blood pressure in the lungs) and fluid is forced out of the blood and into the alveoli – a condition called pulmonary oedema. Oedematous lungs are stiff to inflate and the patient experiences difficulty in breathing (dyspnoea). The irritating effect of fluid in the alveoli is responsible for cough..
Right Ventricular Failure
The most common cause of failure of the right side of the heart is left ventricular failure. Pulmonary hypertension offers resistance to the pumping action of the right side and it too begins to fail. Once again there is a backlog of blood, but this time into the systemic venous circulation (systemic venous hypertension). This leads to oedema in a number of organs, but that in the lower limbs (peripheral oedema) is most obvious since it is manifest as swollen ankles, which pit when gently pressed with the pads of the fingers. 

When left and right ventricular failure occur together, the term congestive cardiac failure is used since pulmonary venous and systemic venous congestion occur.
Activity

What are common symptoms of, and suitable interventions for, congestive cardiac failure? Look on the NHS Direct website to find this information, write your suggestions in the boxes provided, then click on "View answers" to see our suggestions.
Assessment
Match
Match the signs and symptoms on the left with the condition on the right. 

Signs and symptoms	Condition	
Low arterial blood pressure 	Left ventricular failure	
Dyspnoea 	Right ventricular failure	
Pallor		
Swollen ankles		
Cough		
Gapfill
Insert the missing words into the following statement.

"Left ventricular failure leads to _____ arterial blood pressure and _____. It also causes a backlog of blood in the lungs and ______ blood pressure in the pulmonary circulation. This in turn leads to _____, _____ and cough.

Left ventricular failure is the most common cause of right ventricular failure, which is characterised by systemic venous hypertension, _____ and _____."

Missing words:

•	Swollen ankles
•	Dyspnoea
•	Peripheral oedema
•	Decrease
•	Increased
•	Pulmonary oedema 
•	Pallor

Resources

Title/link	Description	
British Heart Foundation 	The BHF is a UK charity dedicated to raising public awareness of heart disease and what they can do to avoid it, and to carrying out research on cardiac conditions. There's a section aimed at healthcare professionals which has a wealth of resources and publications. 	
BMJ Best Treatments 	A compendium of conditions and the "best treatments" for them.	
NHS Direct Online	Comprehensive NHS-run patient-oriented compendium of conditions and treatments. 	

Glossary
•	Alveoli: Air sacs of the lungs across which gas exchange takes place.
•	Atria: The upper chambers of the heart.
•	Cardiac Output: The volume of blood pumped by the heart each minute. It is a product of heart rate and stroke volume.
•	Dyspnoea: The subjective experience of difficulty in breathing.
•	Interstitial fluid: (Tissue Fluid, Intercellular Fluid): The fluid that bathes the cells of the body.
•	Ischaemia: The condition of an inadequate blood supply.
•	Ischaemic Heart Disease (Coronary Artery Disease): Disease of the coronary arteries that leads to ischaemia of the myocardium.
•	Heart Failure (Cardiac Failure): The condition that exists when the heart is unable to maintain a cardiac output sufficient to meets the body’s metabolic needs.
•	Heart rate: The number of times that the heart beats each minute.
•	Hypertension: Elevated blood pressure.
•	Left Ventricular Failure (Left Sided Heart Failure): Heart failure affecting the left ventricle.
•	Myocardial Infarction (Heart Attack): The formation of a thrombus in a coronary artery, which leads to death of part of the myocardium and which may lead to acute heart failure.
•	Myocardium: The heart muscle.
•	Oedema: An excess of interstitial fluid.
•	Pallor: A pale complexion.
•	Right Ventricular Failure (Right Sided Heart Failure): Heart failure affecting the left ventricle.
•	Pulmonary: Pertaining to the lungs.
•	Stroke volume: The volume of blood ejected by the heart at a single contraction.
•	Ventricles: The lower chambers of the heart.

Document updated: 15/10/2008